Process for graining surfaces of irregularly shaped objects



May 28, 1940. Y' H. J. PATT'lsoN 2,202,464

PROCESS FOR' GRAINING SURFACES OF' IRREGULARLY S`HAPED OBJECTS Filed Nov.. 4. 195'/ i Azra-Zar secz'mn.

' /Vqgdlzye Procesal.

-UNITED on a plate which is known the graining plate from the plate lonto the transfer rolls K regularly shaped cial-applicators also has been required. Tins has PATENT oF-FICE* PROCESS FOR SUEFACES OF IRREGULARLX SHAPED OBJECTSl Briggs Mich.,

assignor to Detroit,

Appueetien November 4,- 1931. serial Ne. 172,823

- 5 Claims.

The present invention relates to improvements in a processl for graining curved surfaces such as those of irregularly shaped objects or articles such, for example, as trim moldings used in the construction of motor vehicle bodies.

The, invention pertains in general to the art of ornamenting metal surfaces to simulatethe appearance of a wood grained surface. According to the known methods in this art the surface of an irregularly'shaped -object or article could be grained by printing the grain pattern on the object employing offset methods of printing or lithographing technique. By the offset method the grain `pattern of a master specimen of wood was reproduced usually by photographic methods in the art as a graining plate. 'These plates are of various types and known in the art as surface printing plates, intaglio plates, engraved plates, callotype plates and the like. The design of the grain pattern to be reproduced was formed on these plates, the plates were inked and the transfer of ink to the surfaces of theirregularly shaped article was accomplished by thehuse of elastic transfer rollers which picked up the inked grain pattern from the graining plate and. transferred the pattern'to the surface of the irregularly shaped object. In a particular when applied to the graining of a window trim molding of irregular shape and curved cross section required four separate hand operations in addition to a machine operation in order to ornament the entire exposed surface of the molding. 'I'his method of tern to sucha molding resulted in the formation of more or less straight match lines which indicated the places where the separate operations were performed and indicated breaks in the otherwise more or less continuous grain pattern.

Onev difficulty inherent in conventional processes has been that .the .grainingplates have been surface jupon which the pattern of the master specimen has been reproduced;` When applying the grain pattern from it has heretofore `been necesa plurality of separate impressions andA to transfer the separate impressions to the surface to be grained in such a manner as to avoid the appearance of end grain on the completed surface.

In the graining of thesurfacesof certain irobjectsa large number of`spesary to take added to the cost of equipment for use with the sion isrmade for the automatic regulation of the pressure exerted bythe transfer member on the vinstance this method applying grain patcarrying out the graining operation.

Therefore, it is a principal object of the present invention to provide an improved method of ornamentingv objects having curved surfaces, and particularly the surfaces of irregularly shaped objects or articles by the transfer of an unbroken pattern from the graining plate to the-surface of the object to be grained.

It is a further object of the present invention 10 to provide an improved method of ornamenting the surfaces of irregularly shaped objects in a single operation and in which the entire ornamental pattern is applied at one time.

It is a further object of the present invention to provide an improved method of ornamenting the surfaces of irregularly shaped objects by the transference of the ornamental pattern in a single transfer operation and in which provigraining plate and on the surface ofthe object to be ornamented. Other objects and advantages of the invention will appear in the following descriptionand appended claims,- reference being had to the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding parts. in! the several views. Fig. 1 is a diagrammatic view illustrating the steps of the improved process herein disclosed in making a negative of the master specimen.

Fg.,2 is a diagrammatic view showing the steps in the manufacture of a lgrainingplate fromthe negative made in accordance with the process illustrated in Fig. 1.v

Figs. 3, 4, 5 and 6 are diagrammatic views showing the steps in the transfer of'the image.- from the grainingplate tothe surface of the irregularly shaped object according to the meth-` od of the present invention.

Before explaining in detailthe present inven- Y tion, it is to be understood that the invention is not limited in its application to the details'of construction' and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be-v derstood that the phraseology or terminology employed herein is for vthe purof description and not-of limitation, and itis not intended to-limit the invention claimed herein beyond the requirements of the prior art.

The present method includes vin general the plate is not completely covered with the grained a continuous grain pattern simulating the ap' steps of providing a master specimen of the same size and shape of the irregularly 4shaped object to be ornamented and providing von the surfaces of the master specimen the desired type of ornamentation which is to be reproduced on the surfaces of the irregularly shaped object. In the particular instance hereinafter to be disclosed, by way of example, the surface ornamentation is a grain pattern simulating the appearance of a wood grain. The master specimen in the pre-A ferred example is formed of wood having the desired grain pattern extending in the desired manner around the surfaces of the master specimen. The graining'plate is formed by any desired photographic process in such a manner as to providean inked pattern which corresponds to the shape of the master copy. The graining pattern as in conventional processes but only reproduces the grain pattern in accordance with the grain pattern appearing on the master specimen. The grain pattern is'transferred from the grainingv plate in one operation and as a single unitary pattern directly to'the surface of the irregularly shaped object which is to be ornamented. Any suitable method of transfer is within the scope of the present invention but a preferred methodis that shown in Figs. 34, 5 and 6, which method is also disclosed in my co-pending application 172,822. Y,

The disclosure 'of the method of the present ini vention will proceed with reference to the accompearance of a wood surface.' Itis to be understood, however, that the invention also may be applied to the grainingV of the surfaces. of other irregularly shaped objects such, for example, as van instrument panel, windshield molding or other objects and that the invention is also applicable to the formation of any desired type of surface ornamentation ,in accordance with the method which will be hereinafter more fully disclosed.

According to the process of the present invention I provide a master specimen 2l which as shown in Fig. 1 is preferablyformed of. the ma-l terial having the desired grain or other ornamen tal pattern on the surface thereof. The master specimen may`, however, be formed as of metal or the like and thereafter veneered or ornamented by known hand methods of ornamentation. .The master specimen 20 is lighted by polarized light from a source of .polarized light as for example an electric arc light 2| having a filter '22. An exposure is made in a. photographic camera 23 to form a negative which is thereafter developed,

Y fixed and dried to'produce the completed negative 2l on which appears the outlinev ofV the master specimen and the 'surface ornamentation thereof. Inasmuch as this i's a negative record .A light lines'and the dark portions of the oma-# the dark lines of the surface outline appear as mental pattern appear as light lines on the nega.-

l tive. 'I'he negative '.24 is .then used in accordance.

with the-steps illustrated in Fig. 2 to form the Y -desired graining plates. As shown in Fig. 2, the

negative 2,4' is placed in contactV with a sensitized plate 25 andan exposure is made-with any desiredtype of light or heat rays, such for' example .as light from a source lof .polarized light which may comprise the electric arc light 2i and a filter 21. After the exposure of the sensitized plate 25 hasl been made the plate may be desensitized,

cured and dried in accordance with a conventional 'process indicated by the line A in which instance a graining plate 28 is produced which, as shown in a diagrammatic section outline, has a regular plane surface which, however, is adapted to absorb ink in accordance with variations of the hardness of the previously sensitizedcoating. -If'desired the exposed plate 25 may be treated in accordance with conventional methods as indicated by the line B to form a photoengraved graining plate 29 which, as shown in cross section, has surface irregularities corresponding to the image produced thereon. Other methods are known for forming a graining plate from a photographic negative and any of such methods may be used to provide the desired type of graining plate. Since, however, in accordance with the present invention, the photographic negative contains only the image of the master specimen and the surface ornamentation 'appearing thereon, it is apparent that the graining plate will reproduce in the inked pattern only' the outline of the master vspecimen and the surface appearing thereon.

The graining plate is inked and is `then ready for use in theprocess to effect the transfer of the pattern tothe surface' of the irregularly shaped object as diagrammatically in Figs. 3, 4,

5 6."Other methods of transferring-the vimage from the graining plate to the surface of the irregularly shaped object also may be em-ny pioyed within the scope of the present invention.

ample in Figs. 3, 4, 5 and 6, the methods comprise in general the steps of transferring the image from thev graining plate .to the expanded surface of an inated transfer member, the defiation of the transfer member and contraction of the surface carrying the inked image, the placing of the4 surface to be omamented adjacent the deflated transfer member, the subsequent inflation of the transfer member-and expansion of its surface to bring the inked pattern in contact with the surface of the irregularly shaped ob- .iect to be ornamented until theimage is transl hereinafter referred to as a platen. The platen Il is preferably stationary and formed of a. suitablematerial to provide an' interior chamber Il whichmaybeofanydesiredsiaeandshape.'1he size and shape of .the chamber II may be varied to adapt the platen for use in the various fields where the invention is to be applied. An inlet duct I2 communicates with 'the interior of the chamber Il and is provided with a valve I3 of anydesiredtypewhichcontrolsthesupplyofthe iniiating medium to the chamber; Anv exhaust duct Ilcommimicates with the interlorof the chamber Iland'is provided with a'. valve I5 of l, any desired type to control the discharge of the inflating-medimn from thechamber.

ornamentation4 By the preferred method shown by way of exa resilient transfermember ls, preferably in 70 the form cfa thin sheet of resilient Yrubber of the typeheretoforeus'edin formingrubberdamsin dental work, is secured on its marginal edge portions` to the platen -Il and extends across the open face of the Il. materials '(5 v than the rubber above referred to may bel used to the chamber II the member I6 is dstended and to form the member I6 in accordance with the present invention as long as suchmaterials (1) have a surface capable of picking up the inked image from the plate or roller; (2) are substantially fluid tight; (3) are readily flexible to conform to surface variations; and (4) are-resilient. Various types of natural or artificial rubber sheets are the generally preferred materials for this purpose.

The member I6 is arranged so that upon its ination* by the admission of a fluid under pressure its surface is extended and pressed in contact with a surface' immediately adjacent thereto. Upon release of the fluid pressure, the resiliency of the member I6 causes it to break the Contact with the adjacent surface and to return immediately to its normal position. Thismanner ofbreaking contact with the adjacent surface is important as it insures a clean transfer of the inked image to the transfer member I6 in one instance and the clean transfer of the inked image to the surface of the work piecein the other instance.- Both transfers are accomplished without impairment of the inked image due to blurring frequently caused in commercial processes by a slippage of the transfersurface relative to the surface of the inking'- plate or roller or relative to the surface of the work piece.

Inflation and deflation of the transfer member I6 is caused by a fluid under pressure in the chamber II. Such a fluid in the preferred embodiment here shown is'compressed air but any suitable type of fluid or gas under pressure may be used. The pressure exerted vby such fluid on the member I6 is substantially uniform at all I vpoints and this insures the accurate transfer of I6 after it'has beenplaced in contact `with thev the inked image. The pressure on the member I6 during the process is regulated by the valve I3 which controls both. the amount of. fluid adlirlitted to the chamber I I and the rate of its admission. Deilation of the member `IIB is accomplished by venting the fluid from the chamber I I through the conduit I4 and the valve I5 which controls the rate of discharge of the fluid as well l as the amount of fluid so discharged. In the ease where air is used' as the fluid, the duct I4 vents the air to the atmosphere. Where some other viluid orvgas is employed, the duct I4 may return the material toa supplytank or reservoir.

The operatomof a method embodying the present invention is as follows: The resilient transfer member I6 is placed adjacent the surface of an inked graining plate 28 and is inflated as' shown in Fig. 4 by opening the valve I3 to admit fluid under pressure to the chamber I I and closing the valve I5. This expands the surface of the membe'r I6 in the direction of the inked plate 28 and continued inflation of the member I6 causes the surface of'the member I6 to co e in intimate f contact with the inked surface o the plate 28 and to pick up therefrom the inked image to be transferred to the surface of the' irregularly shaped object. The fluid pressure in the chamber-II is controlledingsuch a manner as to exert any desired amount of "pressure on the member inkedsurface of the plate 28. When the transfer of the inked image to the surface ofthe transfer member I6-.is completed, the valve I3 is 'closed and the valve I5 is'opened and the pressure of the fluid in thechamber II is released., This causes deflation of themember I6 and its return to the normal position as shown in Fig. 3. If desired,

the deation of the member I6 may be accelerated by connection of the duct I4 with a vacuum line. y

After deflation of the member I6 the surface 'of the wo'rk piece 30 to which the ink pattern is tobe transferred is placed adjacent ,the contracted surface of the member I6. The -valve I3- is opened, the valve I5 is closed and the member I6- is again inflated as previously disclosed las shown in Fig. 6. This causes the member I6 to contact the surface of the work piecell and to conform readily to the shape thereof. This con-- dition is maintained until the inked image is transferred from the surface of the transfer member I6 to the surface of the work piece. The pressure of the fluid in the chamber II is released and the member I6 4is drawn laway from the surface of the work piece leaving the inked image or pattern printed thereon.

The surface of the member I6 is then cleaned in any suitable manner andns re-inked for subsequent operations. 'y l In effecting the transfer of the entire ornamental pattern for the surface vof the irregularly shaped object as herein disclosed, it will be apparent that suitable provision must be made as fby'a jig or other fixture to secure proper registration of the transferred image onto the surface of the irregularly shaped work piece. Such devices are known commercially to those skilled in the art and may be of any desired type to accomplish the desired objective.

It will be apparent that the contour of the surface of the irregularly shaped object may be such as to cause a distortion of the image in the photographic negative. The distortion of the image in the photographic negative will be reproduced on the graining plate and will be transierred by the transfer member to the surface of the irregularly shaped object which is to be ornamented. In certain instances particularly in the ornamentation of convex surfaces it will be found that this distortionof the image is not objection-g able vas it creates ancptical illusion which adds to the reality of the transfer pattern.y In other instances, however, this distortion of the image is objectionable but may be overcome in the formation of the negative by methods known to those skilled in the photographic yart as for example by particular placement of the master specimen, particular lighting of the specimen and .particular placement ffthe camera relative to the specimen so as to compensate for the'distortion which might' otherwise appear on the negative and be transferred to the object .to be ornamented. 4. 'f

While the present invention has-been disclosed in a preferred embodiment in which an inflatable resilient transferfmember is utilized, it is to be understood that the transfer may be effected by conventional methods'within the scopeof the present invention. and I do not desire to be r limited by the present disclosure to any particular method of transferring the inked image from theV and ornamentation from the graining plate to the surface of an object having such curved surfaces and corresponding in size and shape to said master pattern.

2. In the method of ornamentlng the surface of objects having curved surfaces, the novel step of providing a master pattern of said object having the desired ornamentation. on the surface thereof, reproducing the entire pattern and ornamentation on` a graining plate by photographic methods, inking the graining plate and transferring in a single loperation the' inked impression from the graining plate to the surface of the lobject by offset printing methods utilizing an elastic transfer member. y

3. In the method of ornamenting the surface of objects having irregular surfaces. thef novel Y step of providing a master pattern of the object having the desired ornamentation on the surface thereof, reproducing the pattern and ornamenta surfaces of anv object, the novel step of 'providing a master pattern of the object having the desired ornamentation on the surface thereof, reproducgraining plate by photographlcmethods, inklng the graining plate and transferring in a single transfer operation the entire inked impression from the graining plate to the irregular surfaces of the object by offset printing methods by inflation of an elastic tr`ansfer member having the inked pattern thereon to bring said member in printing contact with-the surface' to be ornamented. l P

5. In thenmethod of ornamenting objects having curved surfaces, the novel stepof providing a master pattern of the object having the desired ornamentation on the surface thereof, reproducing the entire pattern and ornamentation on a graining plate by photographic methods, inking the graining plate and transferring the entire unbroken inked impression in a single transfer operation from the graining plate to the curved surface or surfaces of the object by offset printing methods by inationof an elastic transfer member having the inked pattern thereon to bring said be ornamented and regulating the inating pressure to insure an intimate contact of the printing surface of the transfer member y'with the contours of said surface to be ornamented.

J. PA'rrIsoN.

ing the entire pattern and ornamentation on a 

